LEDs are one thing, but it's all about the lens. Most of the searchlight signals where I run are lit up by...8 watt bulbs! It's all about the LENS. Think of a Maglight flashlight: That little bulb is powered by 4.5 volts, and properly focused and aimed, a person can see that beam very far away. The searchlights on my district have, for the most part, a roughly 10 inch convex lens that focuses the light into a piercing beam- that beam most readily visible on a foggy night.

Really, no matter how you slice it, properly reacting to signals both good and bad always comes back to diligence and competence.